Although sex is a fundamental component of eukaryotic reproduction, the genetic systems
that control sex determination are highly variable. In many organisms the presence of sex …

Three principal types of chromosomal sex determination are found in nature: male
heterogamety (XY systems, as in mammals), female heterogamety (ZW systems, as in birds) …

Although the X chromosome is usually similar to the autosomes in size and cytogenetic
appearance, theoretical models predict that its hemizygosity in males may cause unusual …

Population genetics theory predicts that X (or Z) chromosomes could play disproportionate
roles in speciation and evolutionary divergence, and recent genome-wide analyses have …

Molecular studies of speciation in birds over the last three decades have been dominated by
a focus on the geography, ecology, and timing of speciation, a tradition traceable to Mayr's …

Identification of genes involved in reproductive isolation opens novel ways to investigate
links between stages of the speciation process. Are the genes coding for ecological …

Current models of X-linked and autosomal evolutionary rates often assume that the effective
population size of the X chromosome (NeX) is equal to three-quarters of the autosomal …

The X or Z chromosome has several characteristics that distinguish it from the autosomes,
namely hemizygosity in the heterogametic sex, and a potentially different effective …

A faster rate of adaptive evolution of X‐linked genes compared with autosomal genes can
be caused by the fixation of recessive or partially recessive advantageous mutations, due to …

Mutation has traditionally been considered a random process, but this paradigm is
challenged by recent evidence of divergence rate heterogeneity in different genomic …